Method of treating electrometallurgical products.



ENT urea.

THOMAS B. ALLEN, OF NIAGARA FALLS, NEW YORK, ASSIGNOR TO THE GARBORUNDUM COMPANY, OF NIAGARA FALLS, NEW YORK, A CORPORATION OF PENNSYLVANIA.

METHOD OF TREATING ELECTROMETALLURGICAL PRODUCTS.

No Drawing.

Specification of Letters Patent. Application filed January 28, 1911. Serial No. 605,329.

Patented Aug. 22, 1911.

To all whom it may concern:

Be it known that I, THOMAS B. ALLEN, a resident of Niagara Falls, in the county of Niagara and State of New York, have invented a new and useful Improvement in Methods of Treating Electrometallurgical Products, of which the following is a full, clear, and exact description.

My invention relates to the manufacture of electrometallurgical products and their after treatment, particularly those used for abrasive and refractory purposes.

The object of the invention is to remove certain impurities which impair or destroy to a large extent the bonding qualities of such products when made up with binders into commercial articles. The method is applicable-t0 a large number of electrometallurgical products, such, for example, as the crystalllne carbids of silicon, titanium and boron and the crystalline aluminous products resultin from the smelting of bauxite and aluminous silicates. Such impurities are usually in the form of carbide and silicides of iron, aluminum and titanium, as well as amorphous material from the unfused part of the charge. These impurities tend to flux the bonding substances used in forming the products into commercial articles, and also have a reducing action on such binders. They are also objectionable for other reasons, and unless removed, the texture and wearing qualities of the articles are varying and ununiform. I have discovered that by mixing such electrometallurgical products with the halid of an alkali or alkaline earth metal, such as sodium chlorid, and subjecting the mixture to heat,

" the impurities can be largely removed and smelting of aluminous silicates with oxid, "of iron and carbon, such as disclosed in the articles formed from such products given increased wearing qualities and better uniformity.

' As a specific example of my invention, I will now describe the process as applied to the aluminous products resulting from the United States Patent No. 906,172, granted to Frank J. Tone on December 8, 1908.. In

the process of this patent, the roduct consists principally of crysta line fused alumina. The ingot of this material is removed ifrom the furnace after cooling and is crushed and screened to the desired sizes metallurgical products of this character,-

the chief impurities are aluminum carbid and ferro silicon. In treating these products with salt at the temperature stated, I have found indicated that the following reactions apparently take place :namely, with ferro silicon the reaction may be written;

Fe,Si lemon- 1F601, SiGl, 16Na .(1)

In the case of aluminum carbid the reaction may be written;

A146, 12NaClT 4AlCl, so 12m 2 My investigations have further indicated that these reactions are reversible, at high temperature going from left to right and at a lower temperature from rlght to left. As is well known in the case of reversible reactions, an equilibrium is established at each temperature depending on the relative con centrations of the different members of the reactions. If, however, one of the members he removed from the sphere of action, the

equilibrium is disturbed, and thus causes a reaction to take place. Hence, if in equation (1) ferric ohlorid or silicon tetra-chlorid or sodium is removed in any manner, the equilibrium is disturbed and fresh quantities of these materials are formed. Under ordinary conditions the removal of all these materials is easily effected since at the temperature of the reaction these materials are volatile. Under these conditions the products on the right hand side of the equation volatilize, more ferric chlorid, silicon tetra-chlorid and sodium are formed, and the reaction can be carried out progressively until all the ferro silicon is decomposed. It is possible to remove the products of the reaction from left to right in both equations (1) and (2) by causing some agent to be present which will react on these substances and remove them from the sphere of action. If for instance, oxygen is introduced, it combines with the sodium in the reaction; represented in (1) and the sodium and carbon in equation (2) these materials are, therefore, removed from the sphere of action, the equilibrium is thereby disturbed and this induces the reaction to take place from left to right until all the impurities are decomposed.

From the above it is apparent how the impurities are removed and an explanation is given of the advantage found by the treatment of electro-metallurgical products with sodium chlorid in the presence of oxygen. However, if ferro silicon or aluminum carbid be heated in the presence of sodium chlorid in a. non-oxidizing or even a reducing temperature, the reactions shown in equations (1). and (2) take place, and if the volatilization of the products of thereaction from left to right takes place it is possible to completely remove these impurities.

Other salts than sodium chlorid may be used for the purpose of my invention, and T have found that the reaction can be carried out or the desired result obtained by the use of the halid compounds of an alkali or alkaline earth metal. I intend to cover such compounds by the use of the words salt of an alkali in my claims.

The advantages of my invention will be obvious to those skilled in the art, since much more uniform articles are obtained and the toughness and wearing quality is improved.

i ooters an alkaline earthmetal, substantially as described.

2. The process of treating electrometallurgical products used for abrasive or refractory purposes, which consists in heating such products with sodium chlorid, substantially as described.

3. The process of treating electrometallurgical products used for abrasive or refractory purposes, which consists in heating such products with sodium chlorid and then removing the reaction products formed by the impurities and the sodium chlorids, substantially as described.

4. The process of treating electrometallur ical products, which consists in heating sists in heating the same with the salt of an alkali in the presence of oxygen; substantially as described.

7. The process of treating impure crystalline alumina, which consists in heating same with sodium chloridin the presence of oxygen; substantially as described.

In testimony whereof, I have hereunto set my hand.

THUS. B. ALLEN.

Witnesses: L. B. CoUL'rER,

P. B. MANLEY. r 

